We got our 2 year old, jesus (pronounced hey zeus) neutered about 3 weeks ago. We were desperately worried, particularly as we had just lost our other boar, gary, and had anything happened to jesus, we just wouldnt have been able to cope. We didnt want him on his own and didnt want to "replace" Gary, so we decided to get jesus neutered and put him in with females.
For all our fears, jesus came out of it very much unscathed, he was fine that evening, eating normal veggies and hay. We had him in a small carrier with a fleecy blanket and a small amount of hay and he was absolutely fine. We watched to make sure he was eating, checked the wound every day to ensure no sign of infection and gave him clean fleece every 2 days but, other than that, we didnt need any special measures. 3 weeks on and he's desperate to get in with the 4 girls, think it could be a bit x-rated


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As an aside, we fed him as normal on the morning of the op (after vets advice), so id ask your vet, but pretty certain he wont need to fast. Our vet also gave us some recovery food but he wasnt interested at all, choosing to eat hay and veggies when he was ready and less groggy.
Hope all goes well